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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
*
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file,
#include "FetchPreloader.h"
#include "mozilla/Assertions.h"
#include "mozilla/CORSMode.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/dom/Document.h"
#include "mozilla/LoadInfo.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/ReferrerInfo.h"
#include "nsContentPolicyUtils.h"
#include "nsContentSecurityManager.h"
#include "nsContentUtils.h"
#include "nsIChannel.h"
#include "nsIChildChannel.h"
#include "nsIClassOfService.h"
#include "nsIHttpChannel.h"
#include "nsIHttpChannelInternal.h"
#include "nsISupportsPriority.h"
#include "nsITimedChannel.h"
#include "nsNetUtil.h"
#include "nsStringStream.h"
#include "nsIDocShell.h"
namespace mozilla {
NS_IMPL_ISUPPORTS(FetchPreloader, nsIStreamListener, nsIRequestObserver)
FetchPreloader::FetchPreloader()
: FetchPreloader(nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD) {}
FetchPreloader::FetchPreloader(nsContentPolicyType aContentPolicyType)
: mContentPolicyType(aContentPolicyType) {}
nsresult FetchPreloader::OpenChannel(const PreloadHashKey& aKey, nsIURI* aURI,
const CORSMode aCORSMode,
const dom::ReferrerPolicy& aReferrerPolicy,
dom::Document* aDocument,
uint64_t aEarlyHintPreloaderId,
int32_t aSupportsPriorityValue) {
nsresult rv;
nsCOMPtr<nsIChannel> channel;
auto notify = MakeScopeExit([&]() {
if (NS_FAILED(rv)) {
// Make sure we notify any <link preload> elements when opening fails
// because of various technical or security reasons.
NotifyStart(channel);
// Using the non-channel overload of this method to make it work even
// before NotifyOpen has been called on this preload. We are not
// switching between channels, so it's safe to do so.
NotifyStop(rv);
}
});
nsCOMPtr<nsILoadGroup> loadGroup = aDocument->GetDocumentLoadGroup();
nsCOMPtr<nsPIDOMWindowOuter> window = aDocument->GetWindow();
nsCOMPtr<nsIInterfaceRequestor> prompter;
if (window) {
nsIDocShell* docshell = window->GetDocShell();
prompter = do_QueryInterface(docshell);
}
rv = CreateChannel(getter_AddRefs(channel), aURI, aCORSMode, aReferrerPolicy,
aDocument, loadGroup, prompter, aEarlyHintPreloaderId,
aSupportsPriorityValue);
NS_ENSURE_SUCCESS(rv, rv);
// Doing this now so that we have the channel and tainting set on it properly
// to notify the proper event (load or error) on the associated preload tags
// when the CSP check fails.
rv = CheckContentPolicy(aURI, aDocument);
if (NS_FAILED(rv)) {
return rv;
}
FetchPreloader::PrioritizeAsPreload(channel);
AddLoadBackgroundFlag(channel);
NotifyOpen(aKey, channel, aDocument, true);
if (aEarlyHintPreloaderId) {
nsCOMPtr<nsIHttpChannelInternal> channelInternal =
do_QueryInterface(channel);
NS_ENSURE_TRUE(channelInternal != nullptr, NS_ERROR_FAILURE);
rv = channelInternal->SetEarlyHintPreloaderId(aEarlyHintPreloaderId);
NS_ENSURE_SUCCESS(rv, rv);
}
return mAsyncConsumeResult = rv = channel->AsyncOpen(this);
}
nsresult FetchPreloader::CreateChannel(
nsIChannel** aChannel, nsIURI* aURI, const CORSMode aCORSMode,
const dom::ReferrerPolicy& aReferrerPolicy, dom::Document* aDocument,
nsILoadGroup* aLoadGroup, nsIInterfaceRequestor* aCallbacks,
uint64_t aEarlyHintPreloaderId, int32_t aSupportsPriorityValue) {
nsresult rv;
nsSecurityFlags securityFlags =
nsContentSecurityManager::ComputeSecurityFlags(
aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
CORS_NONE_MAPS_TO_DISABLED_CORS_CHECKS);
nsCOMPtr<nsIChannel> channel;
rv = NS_NewChannelWithTriggeringPrincipal(
getter_AddRefs(channel), aURI, aDocument, aDocument->NodePrincipal(),
securityFlags, nsIContentPolicy::TYPE_FETCH, nullptr, aLoadGroup,
aCallbacks);
if (NS_FAILED(rv)) {
return rv;
}
AdjustPriority(channel, aSupportsPriorityValue);
if (nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(channel)) {
nsCOMPtr<nsIReferrerInfo> referrerInfo = new dom::ReferrerInfo(
aDocument->GetDocumentURIAsReferrer(), aReferrerPolicy);
rv = httpChannel->SetReferrerInfoWithoutClone(referrerInfo);
MOZ_ASSERT(NS_SUCCEEDED(rv));
}
if (nsCOMPtr<nsITimedChannel> timedChannel = do_QueryInterface(channel)) {
if (aEarlyHintPreloaderId) {
timedChannel->SetInitiatorType(u"early-hints"_ns);
} else {
timedChannel->SetInitiatorType(u"link"_ns);
}
}
channel.forget(aChannel);
return NS_OK;
}
// static
void FetchPreloader::AdjustPriority(nsIChannel* aChannel,
int32_t aSupportsPriorityValue) {
if (nsCOMPtr<nsISupportsPriority> supportsPriority{
do_QueryInterface(aChannel)}) {
supportsPriority->SetPriority(aSupportsPriorityValue);
}
}
nsresult FetchPreloader::CheckContentPolicy(nsIURI* aURI,
dom::Document* aDocument) {
if (!aDocument) {
return NS_OK;
}
nsCOMPtr<nsILoadInfo> secCheckLoadInfo = new net::LoadInfo(
aDocument->NodePrincipal(), aDocument->NodePrincipal(), aDocument,
nsILoadInfo::SEC_ONLY_FOR_EXPLICIT_CONTENTSEC_CHECK, mContentPolicyType);
int16_t shouldLoad = nsIContentPolicy::ACCEPT;
nsresult rv = NS_CheckContentLoadPolicy(aURI, secCheckLoadInfo, &shouldLoad,
nsContentUtils::GetContentPolicy());
if (NS_SUCCEEDED(rv) && NS_CP_ACCEPTED(shouldLoad)) {
return NS_OK;
}
return NS_ERROR_CONTENT_BLOCKED;
}
// PreloaderBase
nsresult FetchPreloader::AsyncConsume(nsIStreamListener* aListener) {
if (NS_FAILED(mAsyncConsumeResult)) {
// Already being consumed or failed to open.
return mAsyncConsumeResult;
}
// Prevent duplicate calls.
mAsyncConsumeResult = NS_ERROR_NOT_AVAILABLE;
if (!mConsumeListener) {
// Called before we are getting response from the channel.
mConsumeListener = aListener;
} else {
// Channel already started, push cached calls to this listener.
// Can't be anything else than the `Cache`, hence a safe static_cast.
Cache* cache = static_cast<Cache*>(mConsumeListener.get());
cache->AsyncConsume(aListener);
}
return NS_OK;
}
// static
void FetchPreloader::PrioritizeAsPreload(nsIChannel* aChannel) {
if (nsCOMPtr<nsIClassOfService> cos = do_QueryInterface(aChannel)) {
cos->AddClassFlags(nsIClassOfService::Unblocked);
}
}
// nsIRequestObserver + nsIStreamListener
NS_IMETHODIMP FetchPreloader::OnStartRequest(nsIRequest* request) {
NotifyStart(request);
if (!mConsumeListener) {
// AsyncConsume not called yet.
mConsumeListener = new Cache();
}
return mConsumeListener->OnStartRequest(request);
}
NS_IMETHODIMP FetchPreloader::OnDataAvailable(nsIRequest* request,
nsIInputStream* input,
uint64_t offset, uint32_t count) {
return mConsumeListener->OnDataAvailable(request, input, offset, count);
}
NS_IMETHODIMP FetchPreloader::OnStopRequest(nsIRequest* request,
nsresult status) {
mConsumeListener->OnStopRequest(request, status);
// We want 404 or other types of server responses to be treated as 'error'.
if (nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(request)) {
uint32_t responseStatus = 0;
Unused << httpChannel->GetResponseStatus(&responseStatus);
if (responseStatus / 100 != 2) {
status = NS_ERROR_FAILURE;
}
}
// Fetch preloader wants to keep the channel around so that consumers like XHR
// can access it even after the preload is done.
nsCOMPtr<nsIChannel> channel = mChannel;
NotifyStop(request, status);
mChannel.swap(channel);
return NS_OK;
}
// FetchPreloader::Cache
NS_IMPL_ISUPPORTS(FetchPreloader::Cache, nsIStreamListener, nsIRequestObserver)
NS_IMETHODIMP FetchPreloader::Cache::OnStartRequest(nsIRequest* request) {
mRequest = request;
if (mFinalListener) {
return mFinalListener->OnStartRequest(mRequest);
}
mCalls.AppendElement(Call{VariantIndex<0>{}, StartRequest{}});
return NS_OK;
}
NS_IMETHODIMP FetchPreloader::Cache::OnDataAvailable(nsIRequest* request,
nsIInputStream* input,
uint64_t offset,
uint32_t count) {
if (mFinalListener) {
return mFinalListener->OnDataAvailable(mRequest, input, offset, count);
}
DataAvailable data;
if (!data.mData.SetLength(count, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
uint32_t read;
nsresult rv = input->Read(data.mData.BeginWriting(), count, &read);
if (NS_FAILED(rv)) {
return rv;
}
mCalls.AppendElement(Call{VariantIndex<1>{}, std::move(data)});
return NS_OK;
}
NS_IMETHODIMP FetchPreloader::Cache::OnStopRequest(nsIRequest* request,
nsresult status) {
if (mFinalListener) {
return mFinalListener->OnStopRequest(mRequest, status);
}
mCalls.AppendElement(Call{VariantIndex<2>{}, StopRequest{status}});
return NS_OK;
}
void FetchPreloader::Cache::AsyncConsume(nsIStreamListener* aListener) {
// Must dispatch for two reasons:
// 1. This is called directly from FetchLoader::AsyncConsume, which must
// behave the same way as nsIChannel::AsyncOpen.
// 2. In case there are already stream listener events scheduled on the main
// thread we preserve the order - those will still end up in Cache.
// * The `Cache` object is fully main thread only for now, doesn't support
// retargeting, but it can be improved to allow it.
nsCOMPtr<nsIStreamListener> listener(aListener);
NS_DispatchToMainThread(NewRunnableMethod<nsCOMPtr<nsIStreamListener>>(
"FetchPreloader::Cache::Consume", this, &FetchPreloader::Cache::Consume,
listener));
}
void FetchPreloader::Cache::Consume(nsCOMPtr<nsIStreamListener> aListener) {
MOZ_ASSERT(!mFinalListener, "Duplicate call");
mFinalListener = std::move(aListener);
// Status of the channel read after each call.
nsresult status = NS_OK;
nsCOMPtr<nsIChannel> channel(do_QueryInterface(mRequest));
RefPtr<Cache> self(this);
for (auto& call : mCalls) {
nsresult rv = call.match(
[&](const StartRequest& startRequest) mutable {
return self->mFinalListener->OnStartRequest(self->mRequest);
},
[&](const DataAvailable& dataAvailable) mutable {
if (NS_FAILED(status)) {
// Channel has been cancelled during this mCalls loop.
return NS_OK;
}
nsCOMPtr<nsIInputStream> input;
rv = NS_NewCStringInputStream(getter_AddRefs(input),
dataAvailable.mData);
if (NS_FAILED(rv)) {
return rv;
}
return self->mFinalListener->OnDataAvailable(
self->mRequest, input, 0, dataAvailable.mData.Length());
},
[&](const StopRequest& stopRequest) {
// First cancellation overrides mStatus in nsHttpChannel.
nsresult stopStatus =
NS_FAILED(status) ? status : stopRequest.mStatus;
self->mFinalListener->OnStopRequest(self->mRequest, stopStatus);
self->mFinalListener = nullptr;
self->mRequest = nullptr;
return NS_OK;
});
if (!mRequest) {
// We are done!
break;
}
bool isCancelled = false;
Unused << channel->GetCanceled(&isCancelled);
if (isCancelled) {
mRequest->GetStatus(&status);
} else if (NS_FAILED(rv)) {
status = rv;
mRequest->Cancel(status);
}
}
mCalls.Clear();
}
} // namespace mozilla